1. Field of the Invention
This invention relates to a flame-retardant and radiation-resistant polymer composition and to a resin molded product prepared therefrom.
2. Description of the Prior Art
Various flame retardants are incorporated in inflammable resins such as polyethylene, polypropylene and ethylenepropylene rubber for the purpose of making them flame retardant. Known flame retardants include halogenated aliphatic compounds such as chlorinated paraffin and chlorinated polyethylene and halogenated aromatic compounds such as hexabromobenzene and decabromodiphenyl ether. The halogenated aliphatic compounds of high molecular weight like chlorinated polyethylene are not greatly compatible with resins and can be used in only few resins such as polyethylene. On the other hand, the halogenated aromatic compounds having a low molecular weight may exude to the surface of the resin upon extended use or evaporate at high temperatures, and in consequence, the flame retardancy of the resin treated with these compounds has a tendency to change with time.
The current criterion for providing safety in nuclear reactors, breeder reactors and ionizing radiation generators is that they use flame-retardant electric wires, cables, and other devices. Therefore, the resin compositions such as insulation coatings of electric wires and cables, electric insulators for various applications, packings, sealants, frames and hoses must be flame retardant and resistant to radiation as well.
U.S. Pat. No. 3,927,145 to Bruno L. Gaeckel et al. discloses that flame resistant characteristics of polyolefins can be improved by incorporating hexabromobiphenyl therein, but does not teach or suggest the improvement of radiation resistance.
U.S. Pat. No. 4,127,559 to Jack Newcombe et al. discloses that halogenated compounds of Diels-Alder adduct can impart flame retardancy to normally flammable organic polymers, but does not teach or suggest the improvement of radiation resistance.
U.S. patent application Ser. No. 114,420, now U.S. Pat. No. 4,289,687, discloses the improvement of fire retardancy of polymers by incorporating monomer of halogenated acenaphthylene compound therein.